1. Field of the Invention
The present invention relates to a burner head for gas burners with a number of gas outlet nozzles for the temperature treatment of profiles, particularly for the temperature treatment of elongated profiles, in which a relative movement between these and the burner head takes place.
2. Description of the Prior Art
Gas burners of the above-mentioned type have been used for a long time and, when supplied with the appropriate gases, for example, hydrogen and oxygen, high operating temperatures for the treatment of the material in question can be reached. Depending on the external form or the external dimensions of the profiles to be treated, the burner types in question show different shapes and dimensions. Thus, the burners can be designed as so-called half-shell ring burners but can also be full-ring burners with or without radial protective veils and so-called free-jet burners, in which the oxygen emerges at high velocity from the individual nozzles of the burner heads. In this case, the burner heads and the nozzles, can be rotatable, tiltable, and variable in their spacings from each other. The latter possibility is also provided by a known gas burner (German Patent 34 00 710), which serves in particular for the heating of glass tubes in the production of preforms for optical glass fibers. The displacement of the individual burner heads relative to each other provided in this known burner and the orientation with respect to the axis of rotation of the glass body to be treated are intended to provide the possibility for providing broad or narrow heating zones, in order to satisfy the requirements of glass fiber production technology.
A disadvantage in this known burner, but also in all previously-mentioned ones, is the fact that, as a result of the opening angle set by the design of the known burner types, a narrow limitation and a sharp edge of the heating zones are not possible. However, narrow temperature limits are important when, for example, regions of a metal band are to be subjected to a continuous annealing process during a temperature treatment or, as already indicated in connection with the above-mentioned patent, broad or narrow heating zones are required for the particular process stages in glass fiber production.